PROJECT SUMMARY (See instructions); Project 5: Stationary Breast Tomosynthesis Breast cancer is the second most common cancer type among women. Over 10% of women develop breast cancer during their lifetimes and 30% to 40% of these patients die from the disease, Early detection is viewed as the best hope to decrease mortality. Full-field digital mammography (FFDM) is the current gold standard for early detection but has it limitations. Digital breast tomosynthesis (DBT), a 3-D imaging technique. Is generally considered to be the next generation screening device with the potential for improved performance compared to FFDM. In the U.S., DBT scanners from 3 leading commercial vendors are in advanced stages of clinical trials. Recent clinical studies have shown that DBT, while having better detection capability for masses compared to FFDM, suffers from lower sensitivity for micro-calcifications (MC) which is critical for early cancer identification. The low MC detectability is attributed mainly to the low image resolution due to motion blurring of both the patient and the x-ray source during the relatively long scanning time. The goal of this project is to develop a novel stationary DBT (s-DBT) technology that has the potential to improve our capability for early detection of human breast tumors. The key enabling technology is the carbon nanotube (CNT) based multi-beam field emission x-ray (MBFEX) that was pioneered by our team. During the first CCNE program, we proposed the s-DBT concept and demonstrated the possibility of constructing a s-DBT scanner with significantly increased scanning speed and spatial resolution compared to the current DBT technology. Our hypothesis is that the high spatial resolution will improve the sensitivity for both masses and micro-calcifications. In addition, the fast scanning speed will reduce patient discomfort due to prolonged compression. For this project we will develop a clinical-test ready prototype s-DBT system and validate its performance through phantom measurements and reader studies. The research will be carried out in close collaboration with Hologic, a market leader in women's healthcare and one of the major developers of the DBT technology.